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Ground Beef Zucchini Casserole

What I like most about this ground beef zucchini bake is how practical it is. You don’t need anything complicated, and it works whether you’re cooking for family, meal prepping for the week, or just trying to use up a couple of zucchinis before they go bad.
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Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour
Course Main Course
Cuisine American
Servings 6 Servings
Calories 320 kcal

Equipment

  • Large skillet
  • 9x13 Baking Dish
  • Cutting board
  • Sharp Knife
  • Mixing Bowl
  • Wooden spoon or spatula
  • Measuring cups and spoons
  • Cheese grater
  • Foil (optional)

Ingredients
  

  • 1 lb ground beef
  • 3 medium zucchini sliced into thin half-moons
  • 1 small yellow onion diced
  • 3 cloves garlic minced
  • 1 tablespoon olive oil
  • 1 teaspoon Italian seasoning
  • 1 teaspoon paprika
  • ½ teaspoon salt
  • ½ teaspoon black pepper
  • 1½ cups marinara sauce
  • 1 cup shredded mozzarella cheese
  • ½ cup shredded cheddar cheese
  • ¼ cup grated parmesan cheese
  • 1 large egg
  • ½ cup sour cream
  • 2 tablespoons chopped fresh parsley optional

Instructions
 

Prepare the oven and baking dish

  • Preheat your oven to 375°F (190°C) so it’s fully hot by the time the casserole is ready to bake.
  • Lightly grease your 9x13 baking dish with cooking spray or a little olive oil. Spread it around the bottom and sides so nothing sticks later.
  • Set the dish aside while you prepare the filling.
  • Pro tip: Greasing the corners well makes serving much easier, especially once the cheese melts around the edges.

Cook the beef mixture

  • Place your large skillet over medium heat and add the olive oil.
  • Once the oil is warm, add the diced onion and cook for about 3–4 minutes, stirring occasionally until it softens.
  • Add the minced garlic and stir for about 30 seconds. You’ll smell it almost immediately — that’s when it’s ready.
  • Add the ground beef and break it apart with a wooden spoon as it cooks.
  • Keep stirring until the beef is fully browned and no pink remains, about 6–8 minutes.
  • Drain any excess grease if needed, especially if your beef releases a lot.
  • Sprinkle in the Italian seasoning, paprika, salt, and black pepper. Stir everything together so the seasoning coats the meat evenly.
  • Pour in the marinara sauce and mix until the beef is well coated. Let it simmer gently for about 4–5 minutes.
  • Pro tip: Letting the sauce simmer for a few minutes deepens the flavor and helps the casserole taste like it cooked much longer.

Prepare the zucchini

  • While the beef simmers, slice the zucchini into thin half-moons.
  • Try to keep the slices about the same thickness so they bake evenly.
  • Place the sliced zucchini on a paper towel and lightly pat them dry.
  • This helps remove some extra moisture before baking.
  • Pro tip: Zucchini naturally releases water while cooking, so drying it first keeps the casserole from turning watery.

Mix the creamy layer

  • In a medium mixing bowl, add the sour cream, egg, and parmesan cheese.
  • Stir until smooth and fully combined.
  • The mixture should look creamy and slightly thick.
  • Set aside until you’re ready to layer.

Assemble the casserole

  • Spread half of the zucchini slices into the bottom of the prepared baking dish.
  • Spoon half of the beef mixture over the zucchini and spread it out evenly.
  • Drop small spoonfuls of the sour cream mixture over the beef layer, then gently spread it.
  • Sprinkle about half of the mozzarella and cheddar over the top.
  • Repeat with the remaining zucchini, then the rest of the beef mixture.
  • Finish by adding the remaining mozzarella and cheddar over the top.
  • Try to spread the cheese evenly so every section gets that golden top layer.

Bake until bubbly

  • Cover the dish loosely with foil.
  • Bake for 20 minutes covered.
  • After 20 minutes, remove the foil and return the casserole to the oven.
  • Bake uncovered for another 15–20 minutes, until the cheese is melted, bubbly, and lightly golden.
  • The zucchini should be tender when pierced with a fork.
  • Pro tip: If you like a browned cheesy top, switch to broil for the last 2–3 minutes — just keep an eye on it.

Let it rest before serving

  • Remove the casserole from the oven and place it on a cooling rack.
  • Let it rest for about 10 minutes before slicing.
  • This gives the layers time to settle and makes serving much cleaner.
  • Sprinkle with fresh parsley if using.
  • Serve warm and scoop out generous portions while the cheese is still melty.

Notes

Nutritional Value (approx. per serving):
  • Calories: 320 kcal
  • Protein: 23 g
  • Carbohydrates: 9 g
  • Fiber: 2 g
  • Sugar: 5 g
  • Fat: 21 g
  • Saturated Fat: 9 g
  • Cholesterol: 85 mg
  • Sodium: 620 mg
  • Potassium: 620 mg
  • Calcium: 220 mg
  • Iron: 2.8 mg
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Nutrition Disclaimer:
The nutritional information provided on this website is an estimate only and is intended for general guidance. We cannot guarantee its accuracy and recommend consulting a qualified healthcare professional or registered dietitian for personalized nutrition advice.